There has been longstanding controversy concerning behavioral or personality characteristics associated with epilepsy, and more recently, with temporal lobe epilepsy in particular. While there are numerous clinical reports of specific behavior syndromes associated with temporal lobe epilepsy, controlled research has generally failed to support their existence. Contributing to this controversy is a lack of adequate definition of the specific behavior patterns being attributed to temporal lobe epilepsy, and as a result, a lack of quantitative methodology for identifying those patterns, making it difficult to determine if temporal lobe epileptics do indeed have a greater incidence of such behavior than do other groups. The purpose of this study is to empirically identify homogeneous subgroups of epileptics who manifest specific patterns of behavioral or personality characteristics. A general sample of outpatient epileptics will be administered several personality inventories designed for use with psychopathological and normal populations, and more specifically, temporal lobe epileptics. Subjects will also participate in a structured interview from which several characteristics purported to be central to the temporal lobe epilepsy behavioral syndrome will be rated and ratings of current, major psychiatric symptoms will be made. These variables will then be used as the basis for a cluster analysis procedure to identify groups of epileptics who are homogeneous with respect to specific patterns of behavior or personality. These groups can then be compared on other variables in order to identify the correlates of those behavior patterns in epileptics. In particular, they can be compared on seizure parameter variables in order to determine if temporal lobe epileptics have differential prevalence of specific behavioral syndromes in comparison to non-temporal lobe epileptics, and to determine if other relevant parameters of the seizure disorders are associated with different behavior patterns. The results of this study can also be used as the basis for developing a quantitative method for identifying and defining specific patterns of behavior in epilepsy that can then be used in further research. Research of this nature may have considerable clinical value in providing a better characterization of the kinds of behavior associated with epilepsy, allowing for more definitive estimates of the incidence of behavior abnormalities in epilepsy. Results of this study may also have significance for delineating the relationship between brain mechanisms and abnormal behavior.